Can I just add: In addition to this, if you struggle with anxiety or have some sort of ADHD, then try cutting out caffeine entirely . Not just switching to "decaf" (which isn't), but cutting out tea and coffee, and switching to an alternative like Barleycup. Doing this has had a massive positive effect for me, and combined with decent nutrition and daily exercise, has been wonderful.
All of these likely got better due to the overall effect of decreased anxiety and not making ADHD worse. I'm not myself when on caffeine. Nikola Tesla quit all caffeine/other stimulants for a reason.